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From: slack@wxlvax.UUCP (Tom Slack)
Newsgroups: net.ai,net.lang.lisp,net.lang.ada
Subject: Re: Multi-language systems
Message-ID: <419@wxlvax.UUCP>
Date: Wed, 20-Mar-85 12:01:28 EST
Article-I.D.: wxlvax.419
Posted: Wed Mar 20 12:01:28 1985
Date-Received: Thu, 21-Mar-85 04:26:29 EST
References: <242@bu-cs.UUCP>, <316@cmu-cs-k.ARPA> <253@bu-cs.UUCP> <494@harvard.ARPA>
Organization: ITT-ATC SRD, Shelton Ct.
Xref: watmath net.ai:2648 net.lang.lisp:409 net.lang.ada:248
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> > I have had the distinctly unpleasant experience of trying to fix a DEC
> > internal system which was written in OPS5, but fired up tasks written in
> > 
> > 	o	BASIC
> > 	o	BLISS
> > 	o	COBOL(!)
> > 
> > Anyone acting in the role of program doctor would have done what I did.
> > I prescribed euthinasia.
> 
> Why can't systems be written in multiple languages? Why can't you just
> plug in the "correct" language for a certain part of a system? Is the
> problem just the data-representation problem? Or is it more deeply
> involved? Maybe the paradigms are sufficiently different in each
> language that no human could be expert enough to handle more than one
> language?
> 
I strongly disagree with the first author.
Until programming languages get out of their own shells (no pun intended),
we will never have reasonably reusable software.
This is one of the reasons that UNIX pipes were invented.
I have recently (three years ago) gone through the process
of moving a LISP program (which I wrote) into PASCAL
through several intermediate stages where PASCAL routines
were called by LISP.
The original program in LISP was about 500 lines.
The current PASCAL implementation is about 3000 lines.
We discovered many details of importance to the application
itself which were hidden by the LISP implementation and
became apparent only after trying to code the problem in PASCAL.

Using LISP in this manner is distictively advantageous at times.
It can also have its difficulties.

The computer industry has just gone through a shake down it
deserved because each cpu believed that it was the center of
the world (hardware wise).
Personal computers are changing all that.
Unfortunately there are still people writing software
systems which want to take over the world (software wise).
Tom Slack
ittvax!wxlvax!slack